target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch

   1 From: Daniel Golle <daniel@makrotopia.org>
   2 Subject: ubi: auto-attach mtd device named "ubi" or "data" on boot
   3
   4 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
   5 ---
   6  drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
   7  1 file changed, 36 insertions(+)
   8
   9 --- a/drivers/mtd/ubi/build.c
  10 +++ b/drivers/mtd/ubi/build.c
  11 @@ -1212,6 +1212,49 @@ static struct mtd_info * __init open_mtd
  12         return mtd;
  13  }
  14
  15 +/*
  16 + * This function tries attaching mtd partitions named either "ubi" or "data"
  17 + * during boot.
  18 + */
  19 +static void __init ubi_auto_attach(void)
  20 +{
  21 +       int err;
  22 +       struct mtd_info *mtd;
  23 +
  24 +       /* try attaching mtd device named "ubi" or "data" */
  25 +       mtd = open_mtd_device("ubi");
  26 +       if (IS_ERR(mtd))
  27 +               mtd = open_mtd_device("data");
  28 +
  29 +       if (!IS_ERR(mtd)) {
  30 +               size_t len;
  31 +               char magic[4];
  32 +
  33 +               /* check for a valid ubi magic */
  34 +               err = mtd_read(mtd, 0, 4, &len, (void *) magic);
  35 +               if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
  36 +                       pr_err("UBI error: no valid UBI magic found inside mtd%d", mtd->index);
  37 +                       put_mtd_device(mtd);
  38 +                       return;
  39 +               }
  40 +
  41 +               /* auto-add only media types where UBI makes sense */
  42 +               if (mtd->type == MTD_NANDFLASH ||
  43 +                   mtd->type == MTD_NORFLASH ||
  44 +                   mtd->type == MTD_DATAFLASH ||
  45 +                   mtd->type == MTD_MLCNANDFLASH) {
  46 +                       mutex_lock(&ubi_devices_mutex);
  47 +                       pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
  48 +                       err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0);
  49 +                       mutex_unlock(&ubi_devices_mutex);
  50 +                       if (err < 0) {
  51 +                               pr_err("UBI error: cannot attach mtd%d", mtd->index);
  52 +                               put_mtd_device(mtd);
  53 +                       }
  54 +               }
  55 +       }
  56 +}
  57 +
  58  static int __init ubi_init(void)
  59  {
  60         int err, i, k;
  61 @@ -1295,6 +1338,12 @@ static int __init ubi_init(void)
  62                 }
  63         }
  64
  65 +       /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
  66 +        * parameter was given */
  67 +       if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
  68 +           !ubi_is_module() && !mtd_devs)
  69 +               ubi_auto_attach();
  70 +
  71         err = ubiblock_init();
  72         if (err) {
  73                 pr_err("UBI error: block: cannot initialize, error %d", err);